1. Field of the Invention
This invention relates to the field of marine dredging.
2. Description of the Related Art
A search of the prior art did not reveal any marine dredging devices that employ the extrusion principle for the transport of dredged soil. However, as my invention is particularly suitable for dredging contaminated marine sediments, the following devices are discussed in this regard.
An apparatus identified by the trade name "Cable Arm Clamshell" is advertised as an environmental dredging device by Cable Arm Incorporated of Trenton, Mich. Their literature states that a patent is pending. This cable operated device differs from a conventional "grab bucket" type of dredge commonly known as a "clamshell bucket" in that it is less prone to spill excess soil due to the buckets forming a nominally closed compartment when the buckets are in the fully closed position.
My invention differs from the Cable Arm device in several aspects. The Cable Arm device must be retrieved from the water to discharge each "bite" of soil and therefore its use involves time wasted traveling through the water column and swinging to discharge the soil. Conversely, my apparatus, once deployed, does not have to be retrieved and is a more efficient continuous production system. My apparatus also incorporates deployable silt curtains which minimize the escape of disturbed soil during the closure of the scoop buckets. The Cable Arm device has no such feature.
A proprietary clamshell dredge is depicted in promotional literature provided by Dow Environmental Incorporated of Rockville, Md. This apparatus appears to be a conventional clamshell bucket with additional metal plating added to the sides and tops of the buckets to provide a nominally closed compartment when the buckets are in the fully closed position. The company's literature makes no claim of patents or patents pending.
My invention differs from the Dow Environmental device in several aspects. Again, my invention is a continuous production system while the Dow Environmental device must be retrieved from the water with each bite of soil. Furthermore, the Dow device does not incorporate deployable silt curtains.
A patent application pertaining to a CONTAMINATED MARINE SEDIMENTS DREDGING APPARATUS was submitted to the United States Commissioner of Patents and Trademarks by this inventor on Jul. 21, 1995. This apparatus must be retrieved from the water with each bite of soil. This invention differs from my previously submitted invention in that it is a continuous production system and thus offers a higher production efficiency.